mobs spawn very rarely and give 1 argent energy even when the sword has loot magic.Also, they do not spawn in fibroids added by the better end and better nether mods.

Loot is intended and spawning is something you have to configure for modded biomes

Will this issue be fixed with the next update?

No, there is no issue here. Everything is working as intended and you must manually add modded biomes to the configs for the mobs

Are there any mods you can give examples?